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300 TDI EDC Fault


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Hi, I have a November 1995 300 Tdi Discovery Auto fitted with EDC, and could do with some advice from people with EDC experience.

The discovery will cruise at 70mph on the level no problem, but when you reach a incline it starts to gradually lose power, at the top of the incline your doing 50mph. When you reach the next incline the disco starts to do it again, but the power loss starts earlier and is more noticable. You can floor the throttle but it makes no difference, the auto won't kick down, so you just sit there slowing down till you reach the top. The disco slows down and down till 50mph when the auto box kicks down and the engine revs increase, the engine sits there revving away but there is no speed gain at all.

The more you try to force the disco up the incline, the only thing that increases is the engine temp, it gradually rises until you creast at which point it comes back down to normal pretty kwick. At the next incline the engine temp climbs earlier and faster, this has forced me to pull off the 70mph major road onto the smaller local roads and the temp comes back down to normal and the disco drives just as it should, not a care in the world. :rolleyes: It appears that the ECU backs off the power when the engine temp starts to rise, even only a slight temp rise.

I tend to do 99% of my own work and have been working through a list of things I can think of, heres what I've done:

EGR removed & plug disconnected

New top intercooler pipe

Inlet manifold cleaned (full of marmite) & new gasket fitted

Turbo waste gate checked, boost pipe from turbo to boost sensor checked.

Cat removed

New silicon intercooler hoses

New standard fit, up rated (brunel) intercooler

New engine temp sensor (previous owner suspected it, as temp guage and infa-red temp probe disagreed)

Replaced 'P' gasket (slight trace of anti freeze around old one)

Visually inspected AFM & air intake pipe.

New air filter

New diesel filter & forte diesel treatment

Diesel sedimenter cleaned, new 'O' rings & drain tap fitted

Timing professionally checked (found to be correct)

Valve clearences checked (all correct)

Engine oil & filter changed

Rad removed, inspected & flushed (leaves removed from between air-con rad and engine rad)

So far it appears that none of this has had any effect on the fault. I got the engine running again at the weekend, and found the alternator started to overcharge the battery (18v) so this was promptly disconntected. Then ran the engine and had fun trying to bleed all the air out of the cooling system, on a short test drive, the MOT's due, it still seems the same :angry:.

When the disco was road tested after the intercooler install, it was noted that the engine will not over fuel, even when flooring it from a standing start.

Any ideas on anything I've overlooked?

I'm considering removing the EDC pump and installing a standard pump. Has anyone removed the EDC system? Anyone know the pitfalls?

I'm thinking I'll need to swap the injector pump, injector pipes, remove the AFM to get it to work. Sound right?

I'm hoping that the (one) EDC injector will work as normal standard injector. I'm not sure how the ECU will behave with major sensors disconneted. I'm thinking that I'll need to keep the ECU to keep the temp guage, immobilizer, and speedo working.

This seems to be the best course of action for me as I need to make the disco reliable, as I will be taking it on expeditions abroad, and don't fancy being stranded on a mountain as the throttle position sensor has just failed, and left me with idle only!

I'll be very grateful for your advice, sorry for the long post but I wanted to give you guys as much info as poss.

Thanks, Buzz.

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Have you tried roadtesting with the Air flow sensor disconnected?

Some systems will default to set values if the sensor is not visible to the ECU.

If it improves, there is a high probability that's the problem.

I also notice you've not replaced the fuel lift-pump.

These can give similar symptoms on their road to failure.

Next port of call (approx £17). ;)

If you did convert to a standard non-EDC pump, it's pretty straight forward.

The EDC injector has only got a needle lift sensor in it, so works as a normal injector.

You'll only need to transfer the ignition feed on the rear of the EDC pump to a stop-solenoid on the

non-EDC pump and you're away. The MAF etc can be left in place but disconnected.

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Hi Imspanners, thanks for your advice. I haven't replaced the lift pump, but a new one was fitted just before I bought the car and I still have the old one, which appears to be in working order.

I hadn't thought about trying it with the MAF disconnected, I'll give that a try next time I'm down the workshop. The autobox has a kick down cable which is connected to a lever on top of the EDC injector pump, which is operated by a cable connected to the throttle pedal. I'm not aware of any connection between the auto box and EDC system, I'll have to have another read of the workshop manual.

Thanks, Buzz.

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If its overheating then I think you need a new radiator. I have seen a lot of early 300Tdis, admittedly mainly Defenders, that are just "on the limit" of what the old radiator can cope with in normal on-road driving either due to a buildup of crud inside the radiator or more commonly because all the small fins between the radiator bars have rotted away with age. Flushing has in many cases been ineffective so we don't even bother trying it now, just fit a new rad. It is also highly likely that the viscous fan will be blitzed as in my experience probably 50% of 300Tdi owners have a viscous fan that is somewhere between less than effective and completely b*ggered but the 300Tdi is so over-cooled (when the rad is in good condition) that you don't really notice!

Fit a new radiator core and see what happens - it could be a self-protection system in the EDC as you suggested. It might not be, but if you want to make it reliable for expeditions and its the original radiator AND its an auto, I'd change it anyway...

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Just a thought but have you checked that the kickdown cable is set correctly?


It will kick down when being driven around town, so it is working, but it is on my list as one of the things to have a fiddle with. I've read the section in the workshop manual about setting it up, so I'll give it a go when its had its mot.

Bogmonster, when flushing the rad I didn't get much out of it at all, but I take your point that it could well be down on performance, and I think it could well be past its first flush of youth! So I'll stick a new one on the list.

The power loss starts first, and the temp starts to rise after you've started to push the engine harder to try and maintain speed up the hill. So I'm not sure about the rad being the cause, but it could well be making the situation much worse by not being able to cool the engine when its under a high load.

Thanks for the advice guys,


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I had same thing happen to my old 300 edc auto, red hot summers day air con on came of motorway into heavy traffic and after about 1/2 hour the elec fan i had fitted could not cope, gauge never moved but the engine went into limp home mode and i had to pull over lift bonnet and let cool for half an hour before i got home and refitted the viscous fan and never had any more bother.

So i reckon replace the rad and thermostat and check the resistance of the fan cold and hot.


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After you get your cooling issues sorted I would get it on Testbook and see if the boost pressure sensor is reading correctly,even tho the EDC version of the Bosch VE pump has better control of fuelling than the mechanical governed ones it should still black smoke when booted.

If it doesnt then the ECU is not seeing the right conditions to give more fuel - even if you boot it.Its much more likely to be a sensor/cabling fault than the pump or ECU - these are both very reliable.

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Ally V8, I asked my local LR specialist if pluging it into test book would help, but they said it wouldn't show anything, admittedly this was before I'd gone through almost everything else I could think of.

When pluging into test book, would a fault be listed? Or would it be a case of dialoging with the ECU real time and see what the sensors are telling it? i.e. no boost pressure.

I'm very suspect of the boost pressure sensor and have been wondering how to test it, thanks for your advice.


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Doesnt sound like your specialist is very special ! Testbook can retrieve logged falut codes from the Ecu and more importantly can show live data from things like the crank sensor,needle lift sensor,boost pressure, ambient presssure/temp,coolant temp etc. Viewing live data with Testbook is how I faultfind most poor running issues,with the Laptop strapped into the passenger seatbelt.Like I said its a good reliable system and there is no reason why it shouldnt be sorted.

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I thought that would be possible, I do a similar thing at work, but with trains.

I tend to keep my ear to the ground and normally hear about most LR faults / strange tendancies, but I hadn't heard much about the EDC system being a problem. Couple that with the fact that the Disco's are all getting on a bit, must mean that so far the components are reliable.

Seeing as you've got experience of the EDC system, how reliable are the throttle position sensors? As I'm a bit worried that this might fail when I'm many miles from a road and leave me with just engine idle speed.

Thanks for your advice,


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  • 6 years later...
I know this goes a long way back, but I've just come across this post regarding the trouble Buzz was having with his 300tdi EDC. I have exactly the same symptons as these on my Disco 97 300tdi EDC auto : lack of power on hills at motorway speed, speed dropping, coolant gauge rising then falling, etc. Did you get to the bottom of this?
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  • 3 weeks later...

Hi, all.

I've just been reading this thread, and I have exactly the same problem with my 1996 300Tdi auto Disco. I haven't noticed the temperature going up, but I have had exactly the same symptoms on hills, especially long or steep ones. Is there much difference between the genuine fuel lift pumps and the cheap ones. I don't mind spending the money, but only if it's worth it. Is the Delphi pump a mid-ranger? Doesn't seem cheapest, or most expensive.



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  • 3 years later...

God day,

I have read this post today first, so this answer is maybe too late.

Anyway, it seems to me that maybe some start in the wrong end of the line.

I suggest:

- Clean and check !!!! the fuel-separator.

- Change fuel-filter

- Change air-filter (!)

- Check the return to tank that it is open.

- Check fuel-pressure (after lifting-pump)

- Run the car with diesel from a separat tank.

Maybe, if you haven´t found any fault, you can have

the high-pressure pump tested. However I will

say it is most likely lack of fuel, nothing else.

Best regards from Sweden

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